JP2002105628A - Vacuum arc vapor deposition apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum arc vapor deposition apparatus capable of forming a thin film having a smooth surface, good adhesion, high purity and good quality on a substrate. SOLUTION: The vacuum arc vapor deposition apparatus is constituted so that a porous member 10 is arranged on the inner wall of a plasma duct 5 provided with a deflection magnetic field forming means having a magnetic coil 8 at its outside, with which the plasma containing a cathode substance generated from a cathode 7 attached to a evaporation source 6 can be guided to the neighborhood of the substrate 11 housed in a film forming chamber 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film forming apparatus for improving characteristics such as abrasion resistance, seizure resistance and slidability of mechanical parts, automobile parts, tools, dies and the like.

[0002]

2. Description of the Related Art Using a vacuum arc evaporation source for evaporating a cathode by vacuum arc discharge to generate a plasma containing a cathode material, ions in the plasma generated by the vacuum arc evaporation source are applied to a substrate by a negative bias voltage or the like. The method of forming a thin film on the surface of a substrate by drawing into a substrate is also called a vacuum arc vapor deposition method, and has features such as a high deposition rate and high adhesion of the thin film.

However, the cathode material evaporated from the vacuum arc evaporation source includes, in addition to fine particles suitable for film formation, coarse particles having a straight diameter of about several μm or more (also called macro particles or droplets). ), And the coarse particles fly and adhere to the substrate, which causes a problem that the adhesion of the thin film to the substrate and the smoothness of the thin film surface are reduced.

In order to overcome this problem, various methods and devices have been proposed.
An apparatus has been proposed in which plasma generated by arc discharge is guided to a substrate, and coarse particles generated at the same time are separated and reduced. Typical examples of this include: I. Aksenov
et al, Sov. J. There is an apparatus described in Plasma Phys. 4 (1978) 425-428. This device is composed of a vacuum arc evaporation source, a curved transport pipe (plasma duct) having a magnetic field forming device outside, and a substrate, so that plasma generated by the vacuum arc evaporation source is guided to the substrate by removing coarse particles. The film forming chamber to be housed is connected to the film forming chamber.

[0005] In recent years, various improved devices for guiding only ions in plasma generated by an evaporation source to a substrate using a magnetic field as described above have been proposed. As an example, Tokio Table 1
The thin film forming apparatus described in Japanese Patent Publication No. 0-505633 will be described below.

The thin film forming apparatus shown in FIG. 2 is substantially perpendicular to a target 33 where an evaporant is generated by arc discharge, and a trigger electrode 35 which comes into contact with the target 33 when a negative voltage is applied to the target 33. A first electromagnet 46 provided on the outside of the plasma duct 39 where the target 33 is provided, and a second electromagnet 48 provided on the bent portion of the plasma duct 39. A third electromagnet 50 is provided on the outlet side of the plasma duct 39 so as to surround the plasma duct 39. A baffle 52 extending inward is provided on the inner wall of the plasma duct 39.
Is provided.

When the trigger electrode 35 comes into contact with the target 33 while a voltage is applied to the target 33,
An arc is instantaneously generated, and this arc is
The target is evaporated while remaining on the surface of No. 3 for a predetermined time to generate a plasma containing the target material.

At this time, the first, second and third electromagnets 46,
When current is applied to 48, 50, the plasma duct 39
Are distributed along the magnetic field lines 40. Accordingly, in the plasma containing the target material generated from the target 33, the charged particles (ions) are moved along the magnetic force lines 40 (deflection magnetic field).
The plasma advances and is sent out from an outlet of the plasma duct 39 into a film forming chamber (not shown), and is vapor-deposited on a substrate (not shown) provided in the chamber. Neutral particles and coarse particles that are not ionized cannot reach the substrate, and the plasma duct 3
9 and a baffle 52 provided on the inner wall of the plasma duct 39.

Therefore, most of the coarse particles adhere to and are removed from the inner wall of the plasma duct 39 and the baffle 52 while traveling in the plasma duct 39.

Also, US Pat. No. 5,279,723
And Japanese Patent Application Laid-Open No. H10-280135 also disclose a similar device. In any case, a metal ring extending inward from the inner wall of the plasma duct is provided on the inner wall of the bent or curved plasma duct so as to capture coarse particles. There is provided a baffle formed of a member or a blade-like member.

However, the conventional structure of the baffle provided on the inner wall of the plasma duct has the following problems. First, as described above, since each of the baffles is formed of a metal ring member or a wing-like member extending inward from the inner wall of the plasma duct, coarse particles are formed in a portion facing perpendicularly to the plasma duct. If it comes, it is attached or reflected in the direction of the cathode, but if it comes in a plane parallel to the plasma duct, it is highly likely that it is reflected in the direction of the substrate.

If a large number of ring-shaped or blade-shaped members are provided in order to bounce many of the coarse particles toward the target, as described above, the number of surfaces parallel to the plasma duct inevitably increases, and the surface is reflected toward the substrate. As the number of coarse particles increases, the possibility that the coarse particles reach the substrate increases, and the smoothness and adhesion of the thin film are hindered.

Second, in order to fix a large number of ring-shaped or blade-shaped members to the inner wall of the plasma duct, it is necessary to screw or weld them to the inner wall. Requires a great deal of processing time and mounting work time, and increases manufacturing costs.
In addition, when the baffle is operated for a long time, the baffle becomes dirty and needs to be replaced. However, it takes a lot of time to replace a large number of baffles.

Third, in the baffle structure as described above, since neutral particles of large and small sizes adhere to the inner wall of the plasma duct and become dirty, it is necessary to remove the dirt at the time of baffle replacement or the like. Not easy.

In addition to the problem of the coarse particles described above, even fine particles suitable for film formation may not be coated on the substrate and may adhere to the inner wall of the film formation chamber. In the above-described apparatus, the structure of the inner wall of the film formation chamber for accommodating the substrate is not described. There is a possibility that the fine particles fall, and these fall into the thin film and deteriorate the film quality.

[0016]

SUMMARY OF THE INVENTION The present invention has been devised in order to solve the above-mentioned problems, and is intended to provide a thin film having a small amount of the coarse particles and fine particles and excellent in smoothness, adhesion and film quality. It is an object of the present invention to provide an apparatus which is formed on a base and which is low in cost and has good workability such as maintenance.

[0017]

An apparatus according to the present invention for achieving the above object comprises a vacuum arc evaporation source for evaporating a cathode by vacuum arc discharge to generate a plasma containing a cathode material, and a substrate. And a curved plasma duct having a deflecting magnetic field forming means outside thereof to remove the coarse particles and guide the plasma generated by the vacuum arc evaporation source to the vicinity of the substrate. In the thin film forming apparatus provided, a porous member is provided on the inner wall of the plasma duct. Further, a porous member is provided on the inner wall of the film formation chamber together with the inner wall of the plasma duct.

According to the vacuum arc vapor deposition apparatus of the present invention, since the porous member having a large adsorption surface area is disposed on the inner wall of the plasma duct, the large particles which have come flying are smaller than those of the prior art. Since the particles enter the holes, they are easy to capture and have good adhesion to the porous member, so that coarse particles that are reflected in the direction of the base and mixed into the thin film can be suppressed.
In the case where the porous member is also provided on the inner wall of the film formation chamber, the fine particles attached to the inner wall of the film formation chamber hardly fall, and the fine particles mixed into the thin film during the film formation can be suppressed.

Here, the porous member for capturing the coarse particles can be constituted by a felt-like or mesh-like member. The felt-like member is obtained by compressing a linear member into a cotton-like shape, and the mesh-like member is a mesh-like member. In particular, when a plurality of mesh-shaped members are used in an overlapping manner, the effect of capturing coarse particles increases.

Further, the porous member may be constituted by a nonwoven fabric, a metal or a nonmetallic porous body. Preferably, the nonwoven fabric is excellent in heat resistance that can withstand a high temperature of 200 ° C. or more if possible. Further, it is desirable that the porous member is made of a material containing a cathode material. The material containing the cathode material is better compatible with the coarse particles or the fine particles than the material not containing the cathode material,
This is because the trapping ability is increased because the adhesive force is increased. Further, even in the case where the cathode material is not contained, the same effect can be obtained by coating the material containing the cathode material element in advance by generally used plating or vapor deposition.

[0021]

FIG. 1 is a schematic sectional view showing an example of a vacuum arc evaporation apparatus according to the present invention. This vacuum arc vapor deposition apparatus includes a film forming chamber 1 that is evacuated by a vacuum exhaust device (not shown), and a holder 2 that holds a substrate 11 on which a film is to be formed is provided therein. The film forming chamber 1 and a later-described plasma duct 5 connected thereto are electrically grounded in this example. Holder 2
Is supported by a support shaft 3 in this example, and is rotated, for example, in the direction A by a drive unit (not shown).

A gas such as an inert gas or a reactive gas is introduced into the film forming chamber 1 as needed. Inert gas is
For example, argon gas. The reactive gas is a gas that reacts with a cathode material generated from a vacuum arc evaporation source to form a compound, for example, nitrogen gas.

In this example, the holder 2 and the substrate 11 held by the holder 2 are supplied with a voltage of, for example, several tens
A negative bias voltage of about -1000 V is applied.
When the thin film or the substrate to be formed is an electrically insulating substance, a positive or negative pulse voltage or a high-frequency voltage may be applied.

One end of the curved plasma duct 5 is provided at the opening of the wall surface of the film forming chamber 1 with the base 11 on the holder 2.
It is connected to face. The inside of the plasma duct 5 is evacuated together with the film forming chamber 1. A vacuum arc evaporation source 6 is connected to the other end of the plasma duct 5. The vacuum arc evaporation source 6 has a cathode (target) 7, and the cathode 7 is locally melted by a vacuum arc discharge between the cathode and the plasma duct 5 which also serves as an anode in this example, to remove the cathode material. It evaporates.

The cathode 7 of the vacuum arc evaporation source 6 is made of a desired material (for example, a pure metal, an alloy, carbon, or the like) according to the type of a thin film to be formed. More specifically, it is made of, for example, a pure metal such as Ti, Cr, Mo, Ta, W, Al, or Cu, an alloy such as TiAl, or graphite (carbon).

A magnetic field curved along the plasma duct 5 is formed on the outer periphery of the plasma duct 5, and the plasma generated by the vacuum arc evaporation source 6 by the magnetic field is used to form a substrate on the holder 2 in the film forming chamber 1. A deflecting magnetic field forming means including a magnetic coil 8 guided to the vicinity of 11 is provided. The magnetic coil 8 is excited by a DC exciting power supply (not shown). A part of the magnetic field lines 9 generated when the magnetic coil 8 is excited is schematically shown in FIG. 1, but substantially along the inner surface of the plasma duct 5.

The magnetic coil 8 used as the magnetic field forming means is a solenoid coil in this example. Instead, a plurality of toroidal coils may be arranged on the outer periphery of the plasma duct. Further, a permanent magnet may be provided.

A porous member 10 is attached to the inner wall of the plasma duct 5. In this example, a porous member 10 is also provided on the inner wall of the film forming chamber 1.

Coarse particles of the cathode material fly from the cathode 7 into the plasma duct 5 by the vacuum arc discharge, and the coarse particles adhere to the porous member 10 and are captured. Since the porous member 10 is porous, it has a large adsorption surface area, and therefore has a high adhering ability, so that the once captured coarse particles are hardly reflected toward the substrate 11. Therefore,
According to the apparatus of the present invention, the plasma from which the coarse particles have been removed can be guided to the vicinity of the substrate along the lines of magnetic force.

Since the porous member 10 captures coarse particles, the porous member 10 has a large adsorption surface area, has a pore size larger than the coarse particles, and is attached to the inner wall of a curved plasma duct. Good luck. Specific examples include felt-like and mesh-like members, non-woven fabrics, and metal or non-metallic porous bodies. In particular, felt-like, mesh-like members, and nonwoven fabrics have elasticity in addition to the above-described characteristics, and absorb kinetic energy of flying coarse particles, and therefore have the effect of reducing reflected energy, and are most preferable.

Further, the porous member 10 may be a material having good compatibility and good adhesion after capturing the flying coarse particles. Therefore, the porous member 10 may be made of a material containing a cathode material evaporated by vacuum arc discharge, or a cathode material. May be constituted by a member coated with a material containing by plating or vapor deposition.

For example, a cathode 7 made of graphite is attached to a vacuum arc evaporation source 6 and the cathode is evaporated to form a base 1.
In the case of forming a carbon film on 1, as the porous member 10, a carbon-containing felt material (carbon felt), a porous carbon material (carbon foam), a carbon mesh material (a carbon wire sewn in a mesh shape) or the like is used. Can be used. When the porous member 10 is made of a material other than carbon, it is also effective to apply a carbon coating to the porous member 10 in advance.

The porous member may be integral or may be divided and attached to the inner wall of the plasma duct. Installation is
It can be easily performed by screwing the both ends of the porous member or the like, so that maintenance such as replacement can be easily performed in a short time. When the porous member is divided and attached to the inner wall of the plasma duct, a plurality of types of porous members may be used.

Further, in the example of FIG. 1, the porous member 10 is also provided on the inner wall of the film forming chamber 1.
Fine particles attached to the inner wall of the substrate do not fall and adhere to the substrate 11 or enter the thin film, and a high-quality thin film having good smoothness and adhesion can be formed.

Further, in the example shown in FIG. 1, the porous member is provided on almost the entire inner wall of the plasma duct. Of course, a member may be provided.

[0036]

As described above, according to the present invention, since the porous member is provided on the inner wall of the curved plasma duct,
It is possible to provide a vacuum arc vapor deposition apparatus that is less expensive to manufacture than a conventional plasma duct baffle and has good workability such as maintenance.

The coarse particles generated by the vacuum arc discharge can be reliably captured, and the plasma from which the coarse particles have been removed can be guided to the vicinity of the substrate on which the film is to be formed. A good quality thin film with good quality can be formed.

When a porous member is also provided on the inner wall of the film forming chamber, it is possible to prevent minute particles adhering to the inner wall of the film forming chamber from falling.
Since it is possible to prevent the adhesion to the substrate and the incorporation into the thin film, a higher quality thin film can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a vacuum arc evaporation apparatus according to the present invention.

FIG. 2 is a sectional view showing an example of a conventional vacuum arc plasma transport device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Film-forming chamber 2 Holder 3 Support shaft 4 Bias power supply 5 Plasma duct 6 Vacuum arc evaporation source 7 Cathode 8 Magnetic coil 9 Magnetic field line 10 Porous member 11 Substrate

Claims (8)

[Claims] 1. A vacuum arc evaporation source for evaporating a cathode by vacuum arc discharge to generate a plasma containing a cathode material, a film forming chamber containing a substrate and being evacuated and evacuated, and a vacuum chamber formed by the vacuum arc evaporation source. In the thin film forming apparatus, a curved plasma duct having a deflecting magnetic field forming means outside thereof to remove the coarse particles and guide the plasma to the vicinity of the substrate,
A vacuum arc vapor deposition apparatus comprising a porous member. 2. A vacuum arc evaporation source for evaporating a cathode by vacuum arc discharge to generate a plasma containing a cathode material, a film formation chamber containing a substrate and evacuated to a vacuum, and a vacuum arc evaporation source generated by the vacuum arc evaporation source. A curved plasma duct having a deflecting magnetic field forming means outside thereof to remove the coarse particles and guide it to the vicinity of the substrate, wherein the plasma duct and the inner wall of both the film forming chamber are formed. A vacuum arc vapor deposition apparatus comprising a porous member. 3. The vacuum arc evaporation apparatus according to claim 1, wherein the porous member is a felt-shaped member. 4. The vacuum arc vapor deposition apparatus according to claim 1, wherein the porous member is a mesh member. 5. The method according to claim 1, wherein the porous member is a nonwoven fabric.
Or the vacuum arc evaporation apparatus according to 2. 6. The vacuum arc vapor deposition apparatus according to claim 1, wherein the porous member is a metal or non-metallic porous body. 7. The vacuum arc evaporation apparatus according to claim 1, wherein the porous member is made of a material containing a cathode material. 8. The vacuum arc vapor deposition apparatus according to claim 1, wherein the porous member is formed of a member coated with a material containing a cathode material.